Various colored contact lenses are known in the art. One class of colored lenses includes “cosmetic” lenses useful for enhancing or changing the apparent color of the wearer's iris. Generally, these lenses include a colored iris section, and the colored contact lenses may include an optical correction, for example, a correction to accommodate farsightedness or nearsightedness of the wearer of the contact lens; alternately, the contact lenses may be provided with the colored iris section solely for cosmetic purposes.
Examples of such contact lenses are disclosed in U.S. Pat. No. 4,582,402. The colored contact lenses of these patents are produced by printing a colored pattern of dots over the iris section on an external surface of the lens. This process involves offset pad printing where a colorant is transferred to the lens surface from a printing pad. A problem of such colored contact lenses is that the surface on which the printed pattern is applied tends be relatively rough, i.e., the colored dots appear as raised bumps on the lens surface. Although it has been proposed to print such a pattern on either the front or back surface of a contact lens, in practice, such printed patterns on generally only printed on the front surface of the lens, such that the printed pattern is in contact with the inner eyelid instead of the cornea, to prevent irritation to the cornea when the contact lens is worn.
Other examples of such contact lenses are disclosed in U.S. Pat. No. 5,018,849. For these colored contact lenses, a translucent layer is formed between two layers of lens material, such that this translucent layer is not in contact with eye tissue when the lens is worn. However, a pattern of colorant is still applied to the external front surface of the lens, such that this colorant contacts the inner eyelid.